The invention relates to detection and identification of foaming and bulking bacteria in order to assess the presence and abundance of these problematic organisms in the biological wastewater treatment processes. Wastewater treatment requires efficient solids separation, which is the separation of treated wastewater (liquid phase) from biomass/bacteria (solid phase). Solids separation problems in the wastewater treatment processes include foaming and bulking. Foaming occurs when specific types of hydrophobic filamentous bacteria overgrow and create foams over the surface area of the treatment equipment, such as the aeration tanks and the secondary clarifiers. Bulking occurs due to the disproportionate growth of specific filamentous bacteria, which detrimentally increases the settling time of the biomass in secondary clarifiers. The occurrence of foaming and bulking can substantially impair treatment plant efficiency. Increased energy and chemical inputs, such as disinfectants, are required to control or eliminate foaming and bulking events. Additionally, these problems result in less effective treatment, as the discharged water often has higher biochemical oxygen demand and total suspended solids, which are negative attributes.
The species which cause foaming and bulking problems have been identified and are known in the art. Foaming is known to be caused by the excessive growth of bacterial species from the genera Microthrix, Nocardia, Skermania, Millisia, Tsukamurella, Rhodococcus, and Gordonia. Due to their staining properties, these filamentous bacteria may be collectively classified as “acid-fast” bacteria. Bulking is known to be caused several types of filamentous bacteria, some of which are sulfur-oxidizing species from the genera Thiothrix and Beggiatoa, and herein may be referred to as “sulfur bacteria” or “sulfur species.” These foaming and bulking bacterial will herein be collectively referred to as “FBB” for “foaming-bulking bacteria.”
While the role of the FBB in foaming and bulking events is known, the study and monitoring of these bacteria is problematic. The presence and abundance of these organisms must be measured in order to (1) understand the operational factors that promote their growth, (2) to assess their abundance and anticipate foaming and bulking events they may cause, (3) to develop effective treatment plant practices and interventions that prevent their growth, and (4) to monitor the efficacy of treatments. Unfortunately, the identification and quantification of these organisms currently requires time-consuming light microscopy analysis, which may be subjective and inaccurate unless supplemented with fluorescence in situ hybridization (FISH) techniques. The use of light microscopy and FISH probes requires expensive equipment, reagents, and highly trained personnel, and is not performed quickly. The expense and required expertise of current FBB identification and quantification methods is generally outside the budget and training of treatment plant personnel.
Thus, there is a need in the art for fast, inexpensive, facile, and accurate methods to assess the presence and abundance of FBB. The inventions described herein fulfill this unmet need.